A student is studying the energetic aspects of artificial satellites that move in uniform circular orbits around a planet.
(a) Define the binding energy of a satellite with respect to the planet it revolves around.
(b) State whether the total mechanical energy of a satellite in a stable circular orbit is positive, negative or zero. Give a qualitative explanation for your answer.
(c) The satellite is slowly taken to an elliptical orbit whose semi-major axis is equal to the radius of its previous circular orbit. Will the magnitude of its total mechanical energy change? Justify your answer without performing any numerical calculation.